Terahertz (THz) light lies in the frequency range between photonics and electronics and holds enormous promise for unique non-ionizing imaging applications, as well as in novel linear and non-linear device development. For example, THz imaging holds promise in the detection of epithelial cancer, in security applications such as detection of explosives and hidden weapons, in the analysis of bio-chemical threats, in quality control etc., among many other useful applications.
Prior art systems have been used to actively image objects in the THz region but, in general, the area imaged was quite small (1 cm2 or less) so that the sample or light source had to be raster scanned or the time required to integrate sufficient signal for detection was increased to many seconds, minutes or even hours.
Most efforts to develop useable imaging systems have focused on the development of ever more sensitive imaging system detectors that can detect THz radiation of very low power, on the order of very small fractions of a watt, i.e. μWatts. This has been primarily due to the need for very powerful THz light generators that require very sophisticated and cumbersome cooling devices to generate even moderately high power THz radiation (on the order of 1 watt) or detectors that were similarly encumbered by the need for burdensome cooling systems to obtain THz images from such relatively higher wattage THz light generators. Even with such highly sophisticated prior art systems, the acquisition of even “still” THz images required from minutes to hours. Hence, the development of “real time” THz based imaging systems such as those that could acquire video images or provide useful detectors for a variety of security applications that require instantaneous image acquisition is and has been stymied.
Accordingly, there remains a need for THz imaging systems that are capable of instantaneously acquiring THz images with all of the attendant benefits that THz imaging can provide such as the detection of plastic weapons in security screening, drug detection in certain epidermal medical and postal inspection applications, food inspection systems, etc.